Colored glass-ceramics having petalite and lithium silicate structures

ABSTRACT

A glass-ceramic article comprises a petalite crystalline phase and a lithium silicate crystalline phase. The weight percentage of each of the petalite crystalline phase and the lithium silicate crystalline phase in the glass-ceramic article are greater than each of the weight percentages of other crystalline phases present in the glass-ceramic article. The glass-ceramic article has a transmittance color coordinate in the CIELAB color space of: L*=from 20 to 90; a*=from −20 to 40; and b*=from −60 to 60 for a CIE illuminant F02 under SCI UVC conditions. In some embodiments, the colorant is selected from the group consisting of TiO2, Fe2O3, NiO, Co3O4, MnO2, Cr2O3, CuO, Au, Ag, and V2O5.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/884,825, filed on May 27, 2020, which claims the benefit of priorityto U.S. Application No. 62/853,953, filed on May 29, 2019, bothapplications being incorporated herein by reference.

BACKGROUND Field

The present specification generally relates to glass and glass-ceramiccompositions and, in particular, to colored glass-ceramic compositionshaving a combination of petalite and lithium silicate phases.

Technical Background

Transparent or white translucent glass-ceramics based onpetalite/lithium disilicate structures may exhibit a combination of highstrength and high fracture toughness. Various industries, including theconsumer electronics industry, desire colored materials with the same orsimilar strength and fracture toughness properties. However, theinclusion of colorants in the precursor glass composition may alter thephase assemblage of the glass-ceramic, thereby reducing the strength andfracture toughness.

Accordingly, a need in the art exists for alternative coloredglass-ceramics having high strength and fracture toughness.

SUMMARY

According to a first aspect, a glass-ceramic article comprises apetalite crystalline phase and a lithium silicate crystalline phase. Theweight percentage of each of the petalite crystalline phase and thelithium silicate crystalline phase in the glass-ceramic article aregreater than the weight percentages of each of the other crystallinephases present in the glass-ceramic article. The glass-ceramic articlehas a transmittance color coordinate in the CIELAB color space of:L*=from 20 to 90; a*=from −20 to 40; and b*=from −60 to 60.

According to a second aspect, a glass-ceramic article comprises apetalite crystalline phase; a lithium silicate crystalline phase; and aresidual glass phase comprising a colorant. The glass-ceramic articlehas a fracture toughness of 1 MPa·m^(1/2) or greater, and theglass-ceramic article has a transmittance color coordinate in the CIELABcolor space of: L*=from 20 to 90; a*=from −20 to 40; and b*=from −60 to60 for a CIE illuminant F02 under SCI UVC conditions.

According to a third aspect, a glass-ceramic article comprises apetalite crystalline phase and a lithium silicate crystalline phase.Each of the petalite crystalline phase and the lithium silicatecrystalline phase in the glass-ceramic article have greater weightpercentages than other crystalline phases present in the glass-ceramicarticle. The glass-ceramic article comprises from 0.01 wt % to 5 wt % ofa colorant selected from the group consisting of TiO₂, Fe₂O₃, NiO,Co₃O₄, MnO₂, Cr₂O₃, CuO, Au, Ag, and V₂O₅. Additionally, theglass-ceramic article has a transmittance color coordinate in the CIELABcolor space of: L*=from 50 to 90; a*=from −20 to 30; and b*=from 0 to 40for a CIE illuminant F02 under SCI UVC conditions.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a composition comprising, in wt %: SiO₂ in anamount of from 55 to 80; Al₂O₃ in an amount of from 2 to 20; Li₂O in anamount of from 5 to 20; P₂O₅ in an amount of from 0.5 to 6; and ZrO₂ inan amount of from 0.2 to 15.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein thecomposition further comprises, in wt %, from 0.01 to 5 of a colorantselected from the group consisting of TiO₂, Fe₂O₃, NiO, Co₃O₄, MnO₂,Cr₂O₃, CuO, Au, Ag, and V₂O₅.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein at least80 wt % of the colorant in the composition is present in a residualglass phase of the glass-ceramic article.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein at least95 wt % of the colorant in the composition is present in a residualglass phase of the glass-ceramic article.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a composition further comprising, in wt %: Auin an amount of from 0.01 to 1.5; or Ag in an amount of from 0.01 to1.5; or Cr₂O₃ in an amount of from 0.05 to 1.0; or CuO in an amount offrom 0.1 to 1.5; or NiO in an amount of from 0.1 to 1.5; or V₂O₅ in anamount of from 0.1 to 2.0; or Co₃O₄ in an amount of from 0.01 to 2.0.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a transmittance color coordinate in the CIELABcolor space of: L*=from 50 to 90; a*=from −20 to 30; and b*=from 0 to 40for a CIE illuminant F02 under SCI UVC conditions.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein the weightpercentage of each of the petalite crystalline phase and the lithiumsilicate crystalline phase in the glass-ceramic article have greaterweight percentages than other crystalline phases present in theglass-ceramic article.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a fracture toughness of 1 MPa·m^(1/2) orgreater.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a Vickers hardness of 600 kgf/mm² or greater.

According to another aspect, the glass-ceramic article comprises theglass-ceramic article of any of the previous aspects, wherein theglass-ceramic article has a ring-on-ring strength of at least 300 MPa.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments described herein, including the detailed description whichfollows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description describe various embodiments and areintended to provide an overview or framework for understanding thenature and character of the claimed subject matter. The accompanyingdrawings are included to provide a further understanding of the variousembodiments, and are incorporated into and constitute a part of thisspecification. The drawings illustrate the various embodiments describedherein, and together with the description serve to explain theprinciples and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of a non-frangible sample after afrangibility test;

FIG. 2 is a representation of a frangible sample after a frangibilitytest;

FIG. 3 is a plot of the transmittance of example glass-ceramiccompositions 1-4 for wavelengths from 200 nm to 800 nm at a samplethickness of 1 mm;

FIG. 4 is a plot of the transmittance of example glass-ceramiccompositions 5-8 for wavelengths from 200 nm to 800 nm at a samplethickness of 1 mm;

FIG. 5 is a plot of the transmittance of example glass-ceramic (solidline) and precursor glass (dashed line) 9 for wavelengths from 200 nm to1100 nm at a sample thickness of 1 mm;

FIG. 6 is a plot of the transmittance of example glass-ceramic (solidline) and precursor glass (dashed line) 10 for wavelengths from 200 nmto 1100 nm at a sample thickness of 1 mm;

FIG. 7 is a plot of the transmittance of example glass-ceramic (solidline) and precursor glass (dashed line) 11 for wavelengths from 200 nmto 1100 nm at a sample thickness of 1 mm;

FIG. 8 is a plot of the transmittance of example glass-ceramic (solidline) and precursor glass (dashed line) 12 for wavelengths from 200 nmto 1100 nm at a sample thickness of 1 mm; and

FIG. 9 is a plot of the transmittance of example glass-ceramic (solidline) and precursor glass (dashed line) 13 for wavelengths from 200 nmto 1100 nm at a sample thickness of 1 mm.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings. Whenever possible,the same reference numerals will be used throughout the drawings torefer to the same or like parts.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. Itwill be further understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint, and independently ofthe other endpoint.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order, nor that with any apparatus specificorientations be required. Accordingly, where a method claim does notactually recite an order to be followed by its steps, or that anyapparatus claim does not actually recite an order or orientation toindividual components, or it is not otherwise specifically stated in theclaims or description that the steps are to be limited to a specificorder, or that a specific order or orientation to components of anapparatus is not recited, it is in no way intended that an order ororientation be inferred, in any respect. This holds for any possiblenon-express basis for interpretation, including: matters of logic withrespect to arrangement of steps, operational flow, order of components,or orientation of components; plain meaning derived from grammaticalorganization or punctuation, and; the number or type of embodimentsdescribed in the specification.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to “a” component includes aspects having two or moresuch components, unless the context clearly indicates otherwise.

As a result of the raw materials and/or equipment used to produce theglass or glass-ceramic composition of various embodiments, certainimpurities or components that are not intentionally added may be presentin the final glass or glass-ceramic composition. Such materials arepresent in the glass or glass-ceramic composition in minor amounts andare referred to herein as “tramp materials.” As used herein, “trampmaterials” may be present in an amount of less than 1000 ppm.

As used herein, a glass or glass-ceramic composition having 0 wt % of acompound is defined as meaning that the compound, molecule, or elementwas not purposefully added to the composition, but the composition maystill comprise the compound, typically in tramp or trace amounts.Similarly, “iron-free,” “sodium-free,” “lithium-free,” “zirconium-free,”“alkali earth metal-free,” “heavy metal-free,” or the like are definedto mean that the compound, molecule, or element was not purposefullyadded to the composition, but the composition may still comprise iron,sodium, lithium, zirconium, alkali earth metals, or heavy metals, etc.,but in approximately tramp or trace amounts (e.g., less than about 1000ppm).

Unless otherwise specified, the concentrations of all constituentsrecited herein are expressed in terms of weight percent (wt %).

In various embodiments, glass-ceramic articles include petalite andlithium silicate as the primary crystalline phases. The lithium silicatecrystal phase may be lithium disilicate or lithium metasilicate. Invarious embodiments, the glass retains a low melting temperature (e.g.,below 1500° C.), yet remains compatible with conventional rolling,molding, and float processes. Additionally, lithium silicate is retainedas a major crystal phase, providing inherently high mechanical strengthand fracture toughness to the glass-ceramic. Petalite, a second majorcrystal phase of the glass-ceramic, has a fine grain size, whichcontributes to the transparency or translucency of the glass-ceramic,and can be ion-exchanged for additional mechanical strength.

As used herein, the terms “glass-based” and/or “glass-based article”mean any material or article made at least partially of glass, includingglass and glass-ceramic materials.

Petalite (LiAlSi₄O₁₀) is a monoclinic crystal possessing athree-dimensional framework structure with a layered structure havingfolded Si₂O₅ layers linked by Li and Al tetrahedral. The Li is intetrahedral coordination with oxygen. Petalite is a lithium source andis used as a low thermal expansion phase to improve the thermaldownshock resistance of glass-ceramic or ceramic parts.

In some embodiments, the weight percentage of the petalite crystallinephase in the glass-ceramic compositions described herein can be in arange from 20 to 70 wt %, 20 to 65 wt %, 20 to 60 wt %, 20 to 55 wt %,20 to 50 wt %, 20 to 45 wt %, 20 to 40 wt %, 20 to 35 wt %, 20 to 30 wt%, 20 to 25 wt %, 25 to 70 wt %, 25 to 65 wt %, 25 to 60 wt %, 25 to 55wt %, 25 to 50 wt %, 25 to 45 wt %, 25 to 40 wt %, 25 to 35 wt %, 25 to30 wt %, 30 to 70 wt %, 30 to 65 wt %, 30 to 60 wt %, 30 to 55 wt %, 30to 50 wt %, 30 to 45 wt %, 30 to 40 wt %, 30 to 35 wt %, 35 to 70 wt %,35 to 65 wt %, 35 to 60 wt %, 35 to 55 wt %, 35 to 50 wt %, 35 to 45 wt%, 35 to 40 wt %, 40 to 70 wt %, 40 to 65 wt %, 40 to 60 wt %, 40 to 55wt %, 40 to 70 wt %, 40 to 45 wt %, 45 to 70 wt %, 45 to 65 wt %, 45 to60 wt %, 45 to 55 wt %, 45 to 50 wt %, 50 to 70 wt %, 50 to 65 wt %, 50to 60 wt %, 50 to 55 wt %, 55 to 70 wt %, 55 to 65 wt %, 55 to 60 wt %,60 to 70 wt %, 60 to 65 wt %, or 65 to 70 wt %, or any and allsub-ranges formed from any of these endpoints.

As noted above, the lithium silicate crystalline phase may be lithiumdisilicate or lithium metasilicate. Lithium disilicate (Li₂Si₂O₅) is anorthorhombic crystal based on corrugated sheets of {Si₂O₅} tetrahedralarrays. The crystals are typically tabular or lath-like in shape, withpronounced cleavage planes. Glass-ceramics based on lithium disilicatehave highly desirable mechanical properties, including high bodystrength and fracture toughness, due to their microstructures ofrandomly-oriented interlocked crystals. This crystal structure forcescracks to propagate through the material via tortuous paths around theinterlocked crystals thereby improving the strength and fracturetoughness. Lithium metasilicate, Li₂SiO₃, has an orthorhombic symmetrywith (Si₂O₆) chains running parallel to the c axis and linked togetherby lithium ions. In some embodiments, the weight percentage of thelithium silicate crystalline phase in the glass-ceramic compositions canbe in a range from 20 to 60 wt %, 20 to 55 wt %, 20 to 50 wt %, 20 to 45wt %, 20 to 40 wt %, 20 to 35 wt %, 20 to 30 wt %, 20 to 25 wt %, 25 to60 wt %, 25 to 55 wt %, 25 to 50 wt %, 25 to 45 wt %, 25 to 40 wt %, 25to 35 wt %, 25 to 30 wt %, 30 to 60 wt %, 30 to 55 wt %, 30 to 50 wt %,30 to 45 wt %, 30 to 40 wt %, 30 to 35 wt %, 35 to 60 wt %, 35 to 55 wt%, 35 to 50 wt %, 35 to 45 wt %, 35 to 40 wt %, 40 to 60 wt %, 40 to 55wt %, 40 to 50 wt %, 40 to 45 wt %, 45 to 60 wt %, 45 to 55 wt %, 45 to50 wt %, 50 to 60 wt %, 50 to 55 wt %, or 55 to 60 wt %, or any and allsub-ranges formed from any of these endpoints.

There are two broad families of lithium disilicate glass-ceramics. Thefirst group comprises those that are doped with ceria and a noble metalsuch as silver. These can be photosensitively nucleated via UV light andsubsequently heat-treated to produce strong glass-ceramics such asFotoceram®. The second family of lithium disilicate glass-ceramics isnucleated by the addition of P₂O₅, wherein the nucleating phase isLi₃PO₄. P₂O₅-nucleated lithium disilicate glass-ceramics have beendeveloped for applications as varied as high-temperature sealingmaterials, disks for computer hard drives, transparent armor, and dentalapplications.

The glasses and glass-ceramics described herein may be genericallydescribed as lithium-containing aluminosilicate glasses orglass-ceramics and comprise SiO₂, Al₂O₃, and Li₂O. In addition to SiO₂,Al₂O₃, and Li₂O, the glasses and glass-ceramics embodied herein mayfurther contain alkali oxides, such as Na₂O, K₂O, Rb₂O, or Cs₂O, as wellas P₂O₅ and ZrO₂, and a number of other components as described below.In one or more embodiments, the major crystallite phases includepetalite and lithium silicate, but β-spodumene solid solution, β-quartzsolid solution, lithium phosphate, cristobalite, and rutile may also bepresent as minor phases depending on the compositions of the precursorglass. In some embodiments, the glass-ceramic composition has a residualglass content of 5 to 30 wt %, 5 to 25 wt %, 5 to 20 wt %, 5 to 15 wt %,5 to 10 wt %, 10 to 30 wt %, 10 to 25 wt %, 10 to 20 wt %, 10 to 15 wt%, 15 to 30 wt %, 15 to 25 wt %, 15 to 20 wt %, 20 to 30 wt %, 20 to 25wt %, or 25 to 30 wt %, as determined according to Rietveld analysis ofthe XRD spectrum. It should be understood that the residual glasscontent may be within a sub-range formed from any and all of theforegoing endpoints.

SiO₂ is the primary glass former and can function to stabilize thenetworking structure of glasses and glass-ceramics. In some embodiments,the glass or glass-ceramic composition comprises from 55 to 80 wt %SiO₂. In some embodiments, the glass or glass-ceramic compositioncomprises from 69 to 80 wt % SiO₂. In some embodiments, the glass orglass-ceramic composition can comprise from 55 to 80 wt %, 55 to 77 wt%, 55 to 75 wt %, 55 to 73 wt %, 60 to 80 wt %, 60 to 77 wt %, 60 to 75wt %, 60 to 73 wt %, 65 to 80 wt %, 65 to 77 wt %, 65 to 75 wt %, 65 to73 wt %, 69 to 80 wt %, 69 to 77 wt %, 69 to 75 wt %, 69 to 73 wt %, 70to 80 wt %, 70 to 77 wt %, 70 to 75 wt %, 70 to 73 wt %, 73 to 80 wt %,73 to 77 wt %, 73 to 75 wt %, 75 to 80 wt %, 75 to 77 wt %, or 77 to 80wt % SiO₂, or any and all sub-ranges formed from any of these endpoints.

The concentration of SiO₂ should be sufficiently high (greater than 55wt %) in order to form petalite crystal phase when the precursor glassis heat-treated to convert to a glass-ceramic. In other words, theconcentration SiO₂, should be high enough to yield both the lithiumsilicate and petalite phases. The amount of SiO₂ may be limited tocontrol melting temperature (200 poise temperature), as the meltingtemperature of pure SiO₂ or high-SiO₂ glasses is undesirably high.

Like SiO₂, Al₂O₃ may also provide stabilization to the network and alsoprovides improved mechanical properties and chemical durability. If theamount of Al₂O₃ is too high, however, the fraction of lithium silicatecrystals may be decreased, possibly to the extent that an interlockingstructure cannot be formed. The amount of Al₂O₃ can be tailored tocontrol viscosity. Further, if the amount of Al₂O₃ is too high, theviscosity of the melt is also generally increased. In some embodiments,the glass or glass-ceramic composition can comprise from 2 to 20 wt %Al₂O₃. In some embodiments, the glass or glass-ceramic composition cancomprise from 6 to 9 wt % Al₂O₃. In some embodiments, the glass orglass-ceramic composition can comprise from 2 to 20 wt %, 2 to 18 wt %,2 to 15 wt %, 2 to 12 wt %, 2 to 10 wt %, 2 to 9 wt %, 2 to 8 wt %, 2 to5 wt %, 5 to 20 wt %, 5 to 18 wt %, 5 to 15 wt %, 5 to 12 wt %, 5 to 10wt %, 5 to 9 wt %, 5 to 8 wt %, 6 to 20 wt %, 6 to 18 wt %, 6 to 15 wt%, 6 to 12 wt %, 6 to 10 wt %, 6 to 9 wt %, 8 to 20 wt %, 8 to 18 wt %,8 to 15 wt %, 8 to 12 wt %, 8 to 10 wt %, 10 to 20 wt %, 10 to 18 wt %,10 to 15 wt %, 10 to 12 wt %, 12 to 20 wt %, 12 to 18 wt %, or 12 to 15wt % Al₂O₃, or any and all sub-ranges formed from any of theseendpoints.

In the glass and glass-ceramics described herein, Li₂O aids in formingboth petalite and lithium silicate crystal phases. To obtain petaliteand lithium silicate as the predominant crystal phases, it is desirableto have at least 7 wt % Li₂O in the composition. However, if theconcentration of Li₂O is too high—greater than 15 wt %—the compositionbecomes very fluid and the delivery viscosity is low enough that a sheetcannot be formed. In some embodied compositions, the glass orglass-ceramic can comprise from 5 wt % to 20 wt % Li₂O. In otherembodiments, the glass or glass-ceramic can comprise from 10 wt % to 14wt % Li₂O. In some embodiments, the glass or glass-ceramic compositioncan comprise from 5 to 20 wt %, 5 to 18 wt %, 5 to 16 wt %, 5 to 14 wt%, 5 to 12 wt %, 5 to 10 wt %, 5 to 8 wt %, 7 to 20 wt %, 7 to 18 wt %,7 to 16 wt %, 7 to 14 wt %, 7 to 12 wt %, 7 to 10 wt %, 10 to 20 wt %,10 to 18 wt %, 10 to 16 wt %, 10 to 14 wt %, 10 to 12 wt %, 12 to 20 wt%, 12 to 18 wt %, 12 to 16 wt %, 12 to 14 wt %, 14 to 20 wt %, 14 to 18wt %, 14 to 16 wt %, 16 to 20 wt %, 16 to 18 wt %, or 18 to 20 wt %Li₂O, or any and all sub-ranges formed from any of these endpoints.

As noted above, Li₂O is generally useful for forming the embodiedglass-ceramics, but the other alkali oxides (e.g., K₂O and Na₂O) tend todecrease glass-ceramic formation and form an aluminosilicate residualglass in the glass-ceramic rather than a ceramic phase. It has beenfound that more than 5 wt % Na₂O or K₂O, or combinations thereof, leadsto an undesirable amount of residual glass which can lead to deformationduring crystallization and undesirable microstructures from a mechanicalproperty perspective. However, levels below 5 wt % may be advantageousfor ion exchange, enabling higher surface compression and/or metrology.In the embodiments described herein, the composition of the residualglass may be tailored to control viscosity during crystallization,minimizing deformation or undesirable thermal expansion, or controlmicrostructure properties. In general, the compositions described hereinhave low amounts of non-lithium alkali oxides. In some embodiments, theglass or glass-ceramic composition can comprise from 0 to 5 wt % R₂O,wherein R is one or more of the alkali cations Na and K. In someembodiments, the glass or glass-ceramic composition can comprise from 1to 3 wt % R₂O, wherein R is one or more of the alkali cations Na and K.In some embodiments, the glass or glass-ceramic composition can comprisefrom 0 to 5 wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt %, 0 to 1 wt %, >0to 5 wt %, >0 to 4 wt %, >0 to 3 wt %, >0 to 2 wt %, >0 to 1 wt %, to 5wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt %, 0 to 1 wt %, 1 to 5 wt %, 1to 4 wt %, 1 to 3 wt %, 1 to 2 wt %, 2 to 5 wt %, 2 to 4 wt %, 2 to 3 wt%, 3 to 5 wt %, 3 to 4 wt %, or 4 to 5 wt % Na₂O, K₂O, or combinationsthereof. It should be understood that the R₂O concentration may bewithin a sub-range formed from any and all of the foregoing endpoints.

The glass and glass-ceramic compositions can include P₂O₅. P₂O₅ canfunction as a nucleating agent to produce bulk nucleation of thecrystalline phase(s) from the glass and glass-ceramic compositions. Ifthe concentration of P₂O₅ is too low, the precursor glass doescrystallize, but only at higher temperatures (due to a lower viscosity);however, if the concentration of P₂O₅ is too high, devitrification uponcooling during precursor glass forming can be difficult to control.Embodiments can comprise from >0 to 6 wt % P₂O₅. Other embodiments cancomprise 2 to 4 wt % P₂O₅. Still other embodiments can comprise 1.5 to2.5 wt % P₂O₅. Embodied compositions can comprise from 0 to 6 wt %, 0 to5.5 wt %, 0 to 5 wt %, 0 to 4.5 wt %, 0 to 4 wt %, 0 to 3.5 wt %, 0 to 3wt %, 0 to 2.5 wt %, 0 to 2 wt %, 0 to 1.5 wt %, 0 to 1 wt %, >0 to 6 wt%, >0 to 5.5 wt %, >0 to 5 wt %, >0 to 4.5 wt %, >0 to 4 wt %, >0 to 3.5wt %, >0 to 3 wt %, >0 to 2.5 wt %, >0 to 2 wt %, >0 to 1.5 wt %, >0 to1 wt %, 0.5 to 6 wt %, 0.5 to 5.5 wt %, 0.5 to 5 wt %, 0.5 to 4.5 wt %,0.5 to 4 wt %, 0.5 to 3.5 wt %, 0.5 to 3 wt %, 0.5 to 2.5 wt %, 0.5 to 2wt %, 0.5 to 1.5 wt %, 0.5 to 1 wt %, 1 to 6 wt %, 1 to 5.5 wt %, 1 to 5wt %, 1 to 4.5 wt %, 1 to 4 wt %, 1 to 3.5 wt %, 1 to 3 wt %, 1 to 2.5wt %, 1 to 2 wt %, 1 to 1.5 wt %, 1.5 to 6 wt %, 1.5 to 5.5 wt %, 1.5 to5 wt %, 1.5 to 4.5 wt %, 1.5 to 4 wt %, 1.5 to 3.5 wt %, 1.5 to 3 wt %,1.5 to 2.5 wt %, 1.5 to 2 wt %, 2 to 6 wt %, 2 to 5.5 wt %, 2 to 5 wt %,2 to 4.5 wt %, 2 to 4 wt %, 2 to 3.5 wt %, 2 to 3 wt %, 2 to 2.5 wt %,2.5 to 6 wt %, 2.5 to 5.5 wt %, 2.5 to 5 wt %, 2.5 to 4.5 wt %, 2.5 to 4wt %, 2.5 to 3.5 wt %, 2.5 to 3 wt %, 3 to 6 wt %, 3 to 5.5 wt %, 3 to 5wt %, 3 to 4.5 wt %, 3 to 4 wt %, 3 to 3.5 wt %, 3.5 to 6 wt %, 3.5 to5.5 wt %, 3.5 to 5 wt %, 3.5 to 4.5 wt %, 3.5 to 4 wt %, 4 to 6 wt %, 4to 5.5 wt %, 4 to 5 wt %, 4 to 4.5 wt %, 4.5 to 6 wt %, 4.5 to 5.5 wt %,4.5 to 5 wt %, 5 to 6 wt %, 5 to 5.5 wt %, or 5.5 to 6 wt % P₂O₅, or anyand all sub-ranges formed from any of these endpoints.

In the glass and glass-ceramics described herein, additions of ZrO₂ canimprove the stability of Li₂O—Al₂O₃—SiO₂—P₂O₅ glass by significantlyreducing glass devitrification during forming and decreasing theliquidus temperature. At concentrations greater than 8 wt %, ZrO₂ canform a primary liquidus phase at a high temperature, which significantlylowers the liquidus viscosity. Transparent glasses can be formed whenthe glass contains over 2 wt % ZrO₂. The addition of ZrO₂ can alsodecrease the petalite grain size, which aids in the formation of atransparent glass-ceramic. In some embodiments, the glass orglass-ceramic composition can comprise from 0.2 to 15 wt % ZrO₂. In someembodiments, the glass or glass-ceramic composition can comprise from 2to 4 wt % ZrO₂. In some embodiments, the glass or glass-ceramiccomposition can comprise from 0.2 to 15 wt %, 0.2 to 12 wt %, 0.2 to 10wt %, 0.2 to 8 wt %, 0.2 to 6 wt %, 0.2 to 4 wt %, 0.5 to 15 wt %, 0.5to 12 wt %, 0.5 to 10 wt %, 0.5 to 8 wt %, 0.5 to 6 wt %, 0.5 to 4 wt %,1 to 15 wt %, 1 to 12 wt %, 1 to 10 wt %, 1 to 8 wt %, 1 to 6 wt %, 1 to4 wt %, 2 to 15 wt %, 2 to 12 wt %, 2 to 10 wt %, 2 to 8 wt %, 2 to 6 wt%, 2 to 4 wt %, 3 to 15 wt %, 3 to 12 wt %, 3 to 10 wt %, 3 to 8 wt %, 3to 6 wt %, 3 to 4 wt %, 4 to 15 wt %, 4 to 12 wt %, 4 to 10 wt %, 4 to 8wt %, 4 to 6 wt %, 8 to 15 wt %, 8 to 12 wt %, 8 to 10 wt %, 10 to 15 wt%, 10 to 12 wt %, or 12 to 15 wt % ZrO₂, or any and all sub-rangesformed from any of these endpoints.

B₂O₃ decreases the melting temperature of the glass precursor.Furthermore, the addition of B₂O₃ in the precursor glass and, thus, theglass-ceramics helps achieve an interlocking crystal microstructure andcan also improve the damage resistance of the glass-ceramic. When boronin the residual glass is not charge balanced by alkali oxides ordivalent cation oxides (such as MgO, CaO, SrO, BaO, and ZnO), it will bein trigonal-coordination state (or three-coordinated boron), which opensup the structure of the glass. The network around thesethree-coordinated boron atoms is not as rigid as tetrahedrallycoordinated (or four-coordinated) boron. Without being bound by theory,it is believed that precursor glasses and glass-ceramics that includethree-coordinated boron can tolerate some degree of deformation beforecrack formation compared to four-coordinated boron. By tolerating somedeformation, the Vickers indentation crack initiation threshold valuesincrease. Fracture toughness of the precursor glasses and glass-ceramicsthat include three-coordinated boron may also increase. Without beingbound by theory, it is believed that the presence of boron in theresidual glass of the glass-ceramic (and precursor glass) lowers theviscosity of the residual glass (or precursor glass), which facilitatesthe growth of lithium silicate crystals, especially large crystalshaving a high aspect ratio. A greater amount of three-coordinated boron(in relation to four-coordinated boron) is believed to result inglass-ceramics that exhibit a greater Vickers indentation crackinitiation load. In some embodiments, the amount of three-coordinatedboron (as a percent of total B₂O₃) may be 40% or greater, 50% orgreater, 75% or greater, 85% or greater, or even 95% or greater. Theamount of boron in general should be controlled to maintain chemicaldurability and mechanical strength of the cerammed bulk glass-ceramic.In other words, the amount of boron should be limited to less than 10 wt% in order to maintain chemical durability and mechanical strength.

In one or more embodiments, the glasses and glass-ceramics herein cancomprise from 0 to 10 wt % or from 0 to 2 wt % B₂O₃. In someembodiments, the glass or glass-ceramic composition can comprise from 0to 10 wt %, 0 to 9 wt %, 0 to 8 wt %, 0 to 7 wt %, 0 to 6 wt %, 0 to 5wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt %, 0 to 1 wt %, >0 to 10 wt%, >0 to 9 wt %, >0 to 8 wt %, >0 to 7 wt %, >0 to 6 wt %, >0 to 5 wt%, >0 to 4 wt %, >0 to 3 wt %, >0 to 2 wt %, >0 to 1 wt %, 1 to 10 wt %,1 to 8 wt %, 1 to 6 wt %, 1 to 5 wt %, 1 to 4 wt %, 1 to 2 wt %, 2 to 10wt %, 2 to 8 wt %, 2 to 6 wt %, 2 to 5 wt %, 2 to 4 wt %, 3 to 10 wt %,3 to 8 wt %, 3 to 6 wt %, 3 to 5 wt %, 3 to 4 wt %, 4 to 10 wt %, 4 to 8wt %, 4 to 6 wt %, 4 to 5 wt %, 5 to 10 wt %, 5 to 8 wt %, 5 to 7.5 wt%, 5 to 6 wt %, or 5 wt % to 5.5 wt % B₂O₃, or any and all sub-rangesformed from any of these endpoints.

MgO can enter petalite crystals in a partial solid solution. In one ormore embodiments, the glasses and glass-ceramics described herein cancomprise from 0 to 8 wt % MgO. In some embodiments, the glass orglass-ceramic composition can comprise from 0 to 8 wt %, %, 0 to 7 wt %,0 to 6 wt %, 0 to 5 wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt %, 0 to 1wt %, >0 to 8 wt %, >0 to 7 wt %, >0 to 6 wt %, >0 to 5 wt %, >0 to 4 wt%, >0 to 3 wt %, >0 to 2 wt %, >0 to 1 wt %, 1 to 8 wt %, 1 to 7 wt %, 1to 6 wt %, 1 to 5 wt %, 1 to 4 wt %, 1 to 3 wt %, 1 to 2 wt %, 2 to 8 wt%, 2 to 7 wt %, 2 to 6 wt %, 2 to 5 wt %, 2 to 4 wt %, 2 to 3 wt %, 3 to8 wt %, 3 to 7 wt %, 3 to 6 wt %, 3 to 5 wt %, 3 to 4 wt %, 4 to 8 wt %,4 to 7 wt %, 4 to 6 wt %, 4 to 5 wt %, 5 to 8 wt %, 5 to 7 wt %, 5 to 6wt %, 6 to 8 wt %, 6 to 7 wt %, or 7 wt % to 8 wt % MgO, or any and allsub-ranges formed from any of these endpoints.

ZnO can enter petalite crystals in a partial solid solution. In one ormore embodiments, the glasses and glass-ceramics herein can comprisefrom 0 to 10 wt % ZnO. In some embodiments, the glass or glass-ceramiccomposition can comprise from 0 to 10 wt %, 0 to 9 wt %, 0 to 8 wt %, 0to 7 wt %, 0 to 6 wt %, 0 to 5 wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt%, 0 to 1 wt %, 1 to 10 wt %, 1 to 9 wt %, 1 to 8 wt %, 1 to 7 wt %, 1to 6 wt %, 1 to 5 wt %, 1 to 4 wt %, 1 to 3 wt %, 1 to 2 wt %, 2 to 10wt %, 2 to 9 wt %, 2 to 8 wt %, 2 to 7 wt %, 2 to 6 wt %, 2 to 5 wt %, 2to 4 wt %, 2 to 3 wt %, 3 to 10 wt %, 3 to 9 wt %, 3 to 8 wt %, 3 to 7wt %, 3 to 6 wt %, 3 to 5 wt %, 3 to 4 wt %, 4 to 10 wt %, 4 to 9 wt %,4 to 8 wt %, 4 to 7 wt %, 4 to 6 wt %, 4 to 5 wt %, 5 to 10 wt %, 5 to 9wt %, 5 to 8 wt %, 5 to 7 wt %, 5 to 6 wt %, 6 to 10 wt %, 6 to 9 wt %,6 to 8 wt %, 6 to 7 wt %, 7 to 10 wt %, 7 to 9 wt %, 7 to 8 wt %, 8 to10 wt %, 8 to 9 wt %, or 9 to 10 wt % ZnO, or any and all sub-rangesformed from any of these endpoints.

TiO₂ may be added to the glass composition in order to provide color tothe glass or glass-ceramic. In one or more embodiments, the glasses andglass-ceramics herein can comprise from 0 to 5 wt % TiO₂. In someembodiments, the glass or glass-ceramic composition can comprise from 0to 5 wt %, 0 to 4 wt %, 0 to 3 wt %, 0 to 2 wt %, 0 to 1 wt %, 1 to 5 wt%, 1 to 4 wt %, 1 to 3 wt %, 1 to 2 wt %, 2 to 5 wt %, 2 to 4 wt %, 2 to3 wt %, 3 to 5 wt %, 3 to 4 wt %, or 4 to 5 wt % TiO₂, or any and allsub-ranges formed from any of these endpoints.

CeO₂ may be added to the glass composition as a fining agent. In one ormore embodiments, the glasses and glass-ceramics herein can comprisefrom 0 to 0.4 wt % CeO₂. In some embodiments, the glass or glass-ceramiccomposition can comprise from 0 to 0.4 wt %, 0 to 0.3 wt %, 0 to 0.2 wt%, 0 to 0.1 wt %, 0.1 to 0.4 wt %, 0.1 to 0.3 wt %, 0.1 to 0.2 wt %, 0.2to 0.4 wt %, 0.2 to 0.3 wt %, or 0.3 wt % to 0.4 wt % CeO₂, or any andall sub-ranges formed from any of these endpoints.

In one or more embodiments, the glasses and glass-ceramics can comprisefrom 0 to 0.5 wt % SnO₂, or another fining agent. In some embodiments,the glass or glass-ceramic composition can comprise from 0 to 0.5 wt %,0 to 0.4 wt %, 0 to 0.3 wt %, 0 to 0.2 wt %, 0 to 0.1 wt %, 0.05 to 0.5wt %, 0.05 to 0.4 wt %, 0.05 to 0.3 wt %, 0.05 to 0.2 wt %, 0.05 to 0.1wt %, 0.1 to 0.5 wt %, 0.1 to 0.4 wt %, 0.1 to 0.3 wt %, 0.1 to 0.2 wt%, 0.2 to 0.5 wt %, 0.2 to 0.4 wt %, 0.2 to 0.3 wt %, 0.3 to 0.5 wt %,0.3 wt % to 0.4 wt %, or 0.4 to 0.5 wt % SnO₂, or any and all sub-rangesformed from any of these endpoints.

In some embodiments, the sum of the weight percentage of P₂O₅ and ZrO₂in the glasses and glass-ceramics can be greater than or equal to 3 wt%, 4 wt %, or 5 wt % to increase nucleation. An increase in nucleationassociated with higher concentrations of these components may lead tothe production of finer grains.

In various embodiments described herein, the glass or glass-ceramicsfurther include from 0.01 to 5 wt % of one or more colorants in the formof transition metal oxides. The colorant may be TiO₂, Fe₂O₃, NiO, Co₃O₄,MnO₂, Cr₂O₃, CuO, Au, Ag, V₂O₅, or combinations thereof. In someembodiments, the glass or glass-ceramic composition may comprise from0.01 to 5 wt %, 0.01 to 4.5 wt %, 0.01 to 4 wt %, 0.01 to 3.5 wt %, 0.01to 3 wt %, 0.01 to 2.5 wt %, 0.01 to 2 wt %, 0.01 to 1.5 wt %, 0.01 to 1wt %, 0.1 to 5 wt %, 0.1 to 4.5 wt %, 0.1 to 4 wt %, 0.1 to 3.5 wt %,0.1 to 3 wt %, 0.1 to 2.5 wt %, 0.1 to 2 wt %, 0.1 to 1.5 wt %, 0.1 to 1wt %, 0.25 to 5 wt %, 0.25 to 4.5 wt %, 0.25 to 4 wt %, 0.25 to 3.5 wt%, 0.25 to 3 wt %, 0.25 to 2.5 wt %, 0.25 to 2 wt %, 0.25 to 1.5 wt %,0.25 to 1 wt %, 0.5 to 5 wt %, 0.5 to 4.5 wt %, 0.5 to 4 wt %, 0.5 to3.5 wt %, 0.5 to 3 wt %, 0.5 to 2.5 wt %, 0.5 to 2 wt %, 0.5 to 1.5 wt%, 0.5 to 1 wt %, 1 to 5 wt %, 1 to 4.5 wt %, 1 to 4 wt %, 1 to 3.5 wt%, 1 to 3 wt %, 1 to 2.5 wt %, or 1 to 2 wt % of a colorant selectedfrom the group consisting of TiO₂, Fe₂O₃, NiO, Co₃O₄, MnO₂, Cr₂O₃, CuO,Au, Ag, and V₂O₅. It should be understood that the colorantconcentration may be within a sub-range formed from any and all of theforegoing endpoints. In some embodiments, when the glass orglass-ceramic composition comprises Au, the composition furthercomprises from 0.05 to 0.5 wt % SnO and/or SnO₂.

In embodiments described herein, the particular amount of colorant maybe selected to achieve a particular pre-determined color of theglass-ceramic. In some embodiments, the glass or glass-ceramiccomposition can comprise one or more of Au in an amount of from 0.01 wt% to 1.5 wt % or from 0.8 wt % to 1.25 wt %; Ag in an amount of from0.01 wt % to 1.5 wt % or 0.8 wt % to 1.25 wt %; Cr₂O₃ in an amount offrom 0.05 wt % to 1.0 wt % or from 0.22 wt % to 0.26 wt %; CuO in anamount of from 0.1 wt % to 1.5 wt % or from 0.8 wt % to 1.25 wt %; NiOin an amount of from 0.1 wt % to 2.0 wt % or from 0.8 wt % to 1.25 wt %;V₂O₅ in an amount of from 0.1 wt % to 2.0 wt % or from 0.8 wt % to 1.25wt %; and/or Co₃O₄ in an amount of from 0.01 wt % to 2.0 wt %. Inembodiments, the glass-ceramic has a transmittance color coordinate inthe CIELAB color space of the following ranges: L*=from 20 to 90;a*=from −20 to 40; and b*=from −60 to 60 for a CIE illuminant F02 underSCI UVC conditions. In some embodiments, the glass-ceramic article has atransmittance color coordinate in the CIELAB color space of thefollowing ranges: L*=from 50 to 90; a*=from −20 to 30; and b*=from 0 to40 for a CIE illuminant F02 under SCI UVC conditions.

In various embodiments described herein, a majority of the colorantremains in the residual glass phase of the glass-ceramic. Accordingly,the colorant may be added without altering the phase assembly of theglass-ceramic. Additionally or alternatively, the colorant adds color tothe glass or glass-ceramic without significantly changing the melting orforming viscosity as compared to an otherwise identical glass orglass-ceramic that does not include the colorant. In one or moreembodiments, at least 80 wt % of the colorant is present in the residualglass phase of the glass-ceramic. In embodiments, at least 80 wt %, atleast 85 wt %, at least 90 wt %, at least 95 wt %, or at least 99 wt %of the colorant is present in the residual glass phase of theglass-ceramic.

In some embodiments, the glass-ceramic is absorbing over the visiblelight range (wavelengths of about 390 nm to about 700 nm). In someembodiments, a glass-ceramic can have an average transmittance in arange from 20% to less than 90% of light over the wavelength range of400 nm to 1000 nm for a glass-ceramic article having a thickness of 1mm.

In some embodiments, the glass or glass-ceramic composition may furtherinclude tramp materials, such as TiO₂, MnO, ZnO, Nb₂O₅, MoO₃, Ta₂O₅,WO₃, Y₂O₃, La₂O₃, HfO₂, CdO, As₂O₃, Sb₂O₃, sulfur-based compounds, suchas sulfates, halogens, or combinations thereof. In some embodiments,antimicrobial components, chemical fining agents, or other additionalcomponents may be included in the glass or glass-ceramic composition.

In some embodiments, the glasses and/or glass-ceramics described hereincan be manufactured into sheets via processes, including, but notlimited to, fusion forming, slot draw, float, rolling, and othersheet-forming processes known to those in the art.

The articles formed from the glass-ceramics described herein can be anysuitable thickness, which may vary depending on the particularapplication for use of the glass-ceramic. Glass sheet and orglass-ceramic embodiments may have a thickness of from 0.4 mm to 10 mm.Some embodiments may have a thickness of 6 mm or less, 5 mm or less, 3mm or less, 2 mm or less, 1.0 mm or less, 750 μm or less, 500 μm orless, or 250 μm or less. Some glass or glass-ceramic sheet embodimentsmay have a thickness of from 200 μm to 5 mm, 500 μm to 5 mm, 200 μm to 4mm, 200 μm to 2 mm, 400 μm to 5 mm, or 400 μm to 2 mm. In someembodiments, the thickness may be from 3 mm to 6 mm or from 0.8 mm to 3mm. It should be understood that the thickness of the article may bewithin a sub-range formed from any and all of the foregoing endpoints.

In some embodiments, the articles formed from the glass-ceramicsdescribed herein have an equibiaxial flexural strength of 300 MPa orgreater, 325 MPa or greater, 350 MPa or greater, 400 MPa or greater, 425MPa or greater, or 450 MPa or greater on a 1 mm thick glass-ceramic. Theequibiaxial flexural strength can also be referred to as a ring-on-ring(RoR) strength, which is measured according to the procedure set forthin ASTM C1499-05, with a few modifications to test fixtures and testconditions as outlined in U.S. Patent Application Publication No.2013/0045375 at paragraph [0027], which is incorporated herein byreference. An abraded ring-on-ring (aRoR) strength can also be measuredusing the procedure described above if the glass-ceramic is firstsubjected to abrasion, typically with silicon carbide particles. Someembodiments also include a chemically-strengthenable glass-ceramic witha petalite phase that leads to increased flexural strength. In suchembodiments, the RoR strength may be 500 MPa or greater, 550 MPa orgreater, 600 MPa or greater, 650 MPa or greater, 700 MPa or greater, 750MPa or greater, or 800 MPa or greater.

Some embodiments of the glass-ceramics exhibit high fracture toughness(K_(Ic)) and an inherent damage resistance. As mentioned above, someembodiments of the glass-ceramic include interlocking lithium silicatecrystals, which result in a high fracture toughness. The glass-ceramicof one or more embodiments may include boron, which may be present asthree-coordinated boron in the residual glass phase of theglass-ceramic, as described herein. In such embodiments, thethree-coordinated boron is provided by the inclusion of B₂O₃ in theprecursor glass.

In one or more embodiments, the glass-ceramics exhibit a fracturetoughness of 1.0 MPa·m^(1/2) or greater, 1.1 MPa·m^(1/2) or greater, 1.2MPa·m^(1/2) or greater, 1.3 MPa·m^(1/2) or greater, 1.4 MPa·m^(1/2) orgreater, 1.5 MPa·m^(1/2) or greater, 1.6 MPa·m^(1/2) or greater, 1.7MPa·m^(1/2) or greater, 1.8 MPa·m^(1/2) or greater, 1.9 MPa·m^(1/2) orgreater, or 2.0 MPa·m^(1/2) or greater. In some embodiments, thefracture toughness is in the range of from 1 to 2 MPa·m^(1/2). It shouldbe understood that the fracture toughness of the glass-ceramics may bewithin a sub-range formed from any and all of the foregoing endpoints.The fracture toughness may be measured using known methods in the art,for example, using a chevron notch short beam test, according to ASTMC1421-10, “Standard Test Methods for Determination of Fracture Toughnessof Advanced Ceramics at Ambient Temperature.”

In one or more embodiments, the glass-ceramics have high crack andscratch resistance, as indicated by a Vickers hardness of at least 600kgf/mm². In some embodiments, a non-ion-exchanged glass-ceramic exhibitsa Vickers hardness in the range of from 600 to 900 kgf/mm², 600 to 875kgf/mm², 600 to 850 kgf/mm², 600 to 825 kgf/mm², 600 to 800 kgf/mm², 600to 775 kgf/mm², 600 to 750 kgf/mm², 600 to 725 kgf/mm², 600 to 700kgf/mm², 700 to 900 kgf/mm², 700 to 875 kgf/mm², 700 to 850 kgf/mm², 700to 825 kgf/mm², 700 to 800 kgf/mm². In some embodiments, theglass-ceramic has a Vickers hardness of 600 kgf/mm² or greater, 625kgf/mm² or greater, 650 kgf/mm² or greater, 675 kgf/mm² or greater, 700kgf/mm² or greater, 725 kgf/mm² or greater, 750 kgf/mm² or greater, 775kgf/mm² or greater, 800 kgf/mm² or greater, 825 kgf/mm² or greater, 850kgf/mm² or greater, 875 kgf/mm² or greater, or 900 kgf/mm² or greater.It should be understood that the Vickers hardness of the glass-ceramicsmay be within a sub-range formed from any and all of the foregoingendpoints. Vickers hardness may be measured according to ASTM C1326 andC1327 (and its progeny, all herein incorporated by reference), “StandardTest Methods for Vickers Indentation Hardness of Advanced Ceramics.” Insome embodiments, the glass-ceramics exhibit such Vickers hardnessvalues after being chemically strengthened via ion-exchange.

In some embodiments, the glass-ceramics disclosed herein are notfrangible upon being ion-exchanged. Frangible behavior refers tospecific fracture behavior when a glass-based article is subjected to animpact or insult. As utilized herein, a glass-based article isconsidered non-frangible when it exhibits at least one of the followingin a test area as the result of a frangibility test: (1) four or lessfragments with a largest dimension of at least 1 mm, and/or (2) thenumber of bifurcations is less than or equal to the number of crackbranches. The fragments, bifurcations, and crack branches are countedbased on any 2 inch by 2 inch square centered on the impact point. Thus,a glass-based article is considered non-frangible if it meets one orboth of tests (1) and (2) for any 2 inch by 2 inch square centered onthe impact point where the breakage is created according to theprocedure described below. In a frangibility test, an impact probe isbrought in to contact with the glass-based article, with the depth towhich the impact probe extends into the glass-based article increasingin successive contact iterations. The step-wise increase in depth of theimpact probe allows the flaw produced by the impact probe to reach thetension region while preventing the application of excessive externalforce that would prevent the accurate determination of the frangiblebehavior of the glass-based article. In one embodiment, the depth of theimpact probe in the glass-based article may increase by about 5 μm ineach iteration, with the impact probe being removed from contact withthe glass-based article between each iteration. The test area is any 2inch by 2 inch square centered at the impact point. FIG. 1 depicts anon-frangible test result. As shown in FIG. 1, the test area is a squarethat is centered at the impact point 130, where the length of a side ofthe square a is 2 inches. The non-frangible sample shown in FIG. 1includes three fragments 142, and two crack branches 140 and a singlebifurcation 150. Thus, the non-frangible sample shown in FIG. 1 containsless than 4 fragments having a largest dimension of at least 1 mm andthe number of bifurcations is less than or equal to the number of crackbranches. As utilized herein, a crack branch originates at the impactpoint, and a fragment is considered to be within the test area if anypart of the fragment extends into the test area. While coatings,adhesive layers, and the like may be used in conjunction with thestrengthened glass-based articles described herein, such externalrestraints are not used in determining the frangibility or frangiblebehavior of the glass-based articles. In some embodiments, a film thatdoes not affect the fracture behavior of the glass-based article may beapplied to the glass-based article prior to the frangibility test toprevent the ejection of fragments from the glass-based article,increasing safety for the person performing the test.

A frangible sample is depicted in FIG. 2. The frangible sample includes5 fragments 142 having a largest dimension of at least 1 mm. The sampledepicted in FIG. 2 includes 2 crack branches 140 and 3 bifurcations 150,producing more bifurcations than crack branches. Thus, the sampledepicted in FIG. 2 does not exhibit either four or less fragments or thenumber of bifurcations being less than or equal to the number of crackbranches.

In the frangibility test described herein, the impact is delivered tothe surface of the glass-based article with a force that is justsufficient to release the internally stored energy present within thestrengthened glass-based article. That is, the point impact force issufficient to create at least one new crack at the surface of thestrengthened glass-based article and extend the crack through thecompressive stress CS region (i.e., depth of compression) into theregion that is under central tension CT. As used herein, “depth ofcompression” (DOC) means the depth at which the stress in the chemicallystrengthened article described herein changes from compressive totensile.

Accordingly, the chemically strengthened glasses described herein are“non-frangible”—i.e., they do not exhibit frangible behavior asdescribed hereinabove when subjected to impact by a sharp object.

In addition, various embodiments of the glass and glass-ceramiccompositions are ion exchangeable by those methods widely known in theart. In typical ion exchange processes, smaller metal ions in the glassare replaced or “exchanged” with larger metal ions of the same valencewithin a layer that is close to the outer surface of the glass and/orglass-ceramic. The replacement of smaller ions with larger ions createsa compressive stress within the layer of the glass and/or glass-ceramic.In one embodiment, the metal ions are monovalent metal ions (e.g., Na⁺,K⁺, and the like), and ion exchange is accomplished by immersing theglass and/or glass-ceramic in a bath comprising at least one molten saltof the larger metal ion that is to replace the smaller metal ion in theglass or glass-ceramic. Alternatively, other monovalent ions such asAg⁺, Tl⁺, Cu⁺, and the like may be exchanged for monovalent ions. Theion exchange process or processes that are used to strengthen the glassand/or glass-ceramic can include, but are not limited to, immersion in asingle bath or multiple baths of like or different compositions withwashing and/or annealing steps between immersions. In one or moreembodiments, the glasses and/or glass-ceramics may be ion exchanged byexposure to molten NaNO₃ at a temperature of 430° C. In suchembodiments, the Na⁺ ions replace some portion of the Li ions in theglass-ceramic to develop a surface compressive layer and exhibit highcrack resistance. The resulting compressive stress layer may have adepth (also referred to as a “depth of compression”) of at least 100 μmon the surface of the glass-ceramic in 2 hours. In such embodiments, thedepth of compression can be determined from the Na₂O concentrationprofile. In other examples, embodiments may be ion exchanged by exposureto molten KNO₃ at a temperature of 410° C. for 2 hours to produce adepth of compression of at least 10 μm. In some embodiments, theglass-ceramics may be ion exchanged to achieve a depth of compression of10 μm or greater, 20 μm or greater, 30 μm or greater, 40 μm or greater,50 μm or greater, 60 μm or greater, 70 μm or greater, 80 μm or greater,90 μm or greater, or 100 μm or greater. In other embodiments, theglass-ceramics are ion exchanged to achieve a central tension of atleast 10 MPa. The development of this surface compression layer isbeneficial for achieving a better crack resistance and higher flexuralstrength compared to non-ion-exchanged materials. The surfacecompression layer has a higher concentration of the ion exchanged intothe glass-ceramic article in comparison to the concentration of the ionexchanged into the glass-ceramic article for the body (i.e., area notincluding the surface compression) of the glass-ceramic article.

In some embodiments, the glass-ceramic can have a surface compressivestress in a range from 100 MPa to 500 MPa, 100 MPa to 450 MPa, 100 MPato 400 MPa, 100 MPa to 350 MPa, 100 MPa to 300 MPa, 100 MPa to 250 MPa,100 MPa to 200 MPa, 100 MPa to 150 MPa, 150 MPa to 500 MPa, 150 MPa to450 MPa, 150 MPa to 400 MPa, 150 MPa to 350 MPa, 150 MPa to 300 MPa, 150MPa to 250 MPa, 150 MPa to 200 MPa, 200 MPa to 500 MPa, 200 MPa to 450MPa, 200 MPa to 400 MPa, 200 MPa to 350 MPa, 200 MPa to 300 MPa, 200 MPato 250 MPa, 250 MPa to 500 MPa, 250 MPa to 450 MPa, 250 MPa to 400 MPa,250 MPa to 350 MPa, 250 MPa to 300 MPa, 300 MPa to 500 MPa, 300 MPa to450 MPa, 300 MPa to 400 MPa, 300 MPa to 350 MPa, 350 MPa to 500 MPa, 350MPa to 450 MPa, 350 MPa to 400 MPa, 400 MPa to 500 MPa, 400 MPa to 450MPa, or 450 MPa to 500 MPa, or any and all sub-ranges formed from any ofthese endpoints. In some embodiments, the glass-ceramic can have asurface compressive stress of 100 MPa or greater, 150 MPa or greater,200 MPa or greater, 250 MPa or greater, 300 MPa or greater, 350 MPa orgreater, 400 MPa or greater, 450 MPa or greater, or 500 MPa or greater.Compressive stress (including surface compressive stress) is measuredwith a surface stress meter (FSM) such as commercially availableinstruments such as the FSM-6000, manufactured by Orihara IndustrialCo., Ltd. (Japan). Surface stress measurements rely upon the accuratemeasurement of the stress optical coefficient (SOC), which is related tothe birefringence of the glass-ceramic. SOC in turn is measuredaccording to Procedure C (Glass Disc Method) described in ASTM standardC770-16, entitled “Standard Test Method for Measurement of GlassStress-Optical Coefficient,” the contents of which are incorporatedherein by reference in their entirety. Depth of compression (DOC) isalso measured with the FSM. The maximum central tension (CT) values aremeasured using a scattered light polariscope (SCALP) technique known inthe art.

In one or more embodiments, the processes for making the glass-ceramicincludes heat treating the precursor glasses at one or more preselectedtemperatures for one or more preselected times to induce glasshomogenization and crystallization (i.e., nucleation and growth) of oneor more crystalline phases (e.g., having one or more compositions,amounts, morphologies, sizes or size distributions, etc.). In someembodiments, the heat treatment can include (i) heating precursorglasses at a rate of 1-10° C./min to a glass pre-nucleation temperature;(ii) maintaining the crystallizable glasses at the pre-nucleationtemperature for a time in a range from ¼ hour to 4 hours to producepre-nucleated crystallizable glasses; (iii) heating the pre-nucleatedcrystallizable glasses at a rate of 1-10° C./min to a nucleationtemperature (Tn); (iv) maintaining the crystallizable glasses at thenucleation temperature for a time in the range from between ¼ hour to 4hours to produce nucleated crystallizable glasses; (v) heating thenucleated crystallizable glasses at a rate in the range from 1° C./minto 10° C./min to a crystallization temperature (Tc); (vi) maintainingthe nucleated crystallizable glasses at the crystallization temperaturefor a time in a range from ¼ hour to 4 hour to produce the glass-ceramicdescribed herein; and (vii) cooling the formed glass-ceramic to roomtemperature.

As used herein, the term “crystallization temperature” may be usedinterchangeably with “ceram temperature” or “ceramming temperature.” Inaddition, the terms “ceram” or “ceramming” in these embodiments, may beused to refer to steps (v), (vi) and optionally (vii), collectively. Insome embodiments, the glass pre-nucleation temperature can be 540° C.,the nucleation temperature can be 600° C., and the crystallizationtemperature can be in a range from 630° to 730° C. In other embodiments,the heat treatment does not include maintaining the crystallizableglasses at a glass pre-nucleation temperature. Thus, the heat treatmentmay include (i) heating the pre-nucleated crystallizable glasses at arate of 1-10° C./min to a nucleation temperature (Tn); (ii) maintainingthe crystallizable glasses at the nucleation temperature for a time inthe range from between ¼ hour to 4 hours to produce nucleatedcrystallizable glasses; (iii) heating the nucleated crystallizableglasses at a rate in the range from 1° C./min to 10° C./min to acrystallization temperature (Tc); (iv) maintaining the nucleatedcrystallizable glasses at the crystallization temperature for a time ina range from ¼ hour to 4 hours to produce the glass-ceramic describedherein; and (v) cooling the formed glass-ceramic to room temperature.The terms “ceram” and “ceramming” in the preceding embodiments may beused to refer to steps (iii), (iv) and optionally (v), collectively. Insome embodiments, the nucleation temperature can be 700° C., and thecrystallization temperature can be 800° C. In some embodiments, thehigher the crystallization temperature, the more β-spodumene solidsolution is produced as a minor crystalline phase.

Temperature-temporal profiles of heat treatment steps of heating to thecrystallization temperature and maintaining the temperature at thecrystallization temperature in addition to precursor glass compositionsare judiciously prescribed so as to produce one or more of the followingdesired attributes: crystalline phase(s) of the glass-ceramic,proportions of one or more major crystalline phases and/or one or moreminor crystalline phases and residual glass, crystal phase assemblagesof one or more predominate crystalline phases and/or one or more minorcrystalline phases and residual glass, and grain sizes or grain sizedistribution among one or more major crystalline phases and/or one ormore minor crystalline phases, which in turn may influence the finalintegrity, quality, color, and/or opacity of the resultantglass-ceramic.

The resultant glass-ceramic can be provided as a sheet, which can thenbe reformed by pressing, blowing, bending, sagging, vacuum forming, orother means into curved or bent pieces of uniform thickness. Reformingcan be done before thermally treating or the forming step can also serveas a thermal treatment step in which both forming and thermal treatingare performed substantially simultaneously.

The glass-ceramics and glass-ceramic articles described herein can beused for a variety of applications including, for example, for coverglass or glass backplane applications in consumer or commercialelectronic devices including, for example, LCD and LED displays,computer monitors, and automated teller machines (ATMs); for touchscreen or touch sensor applications, for portable electronic devicesincluding, for example, mobile telephones, personal media players, andtablet computers; for integrated circuit applications including, forexample, semiconductor wafers; for photovoltaic applications; forarchitectural glass applications; for automotive or vehicular glassapplications; or for commercial or household appliance applications. Invarious embodiments, a consumer electronic device (e.g., smartphones,tablet computers, personal computers, ultrabooks, televisions, andcameras), an architectural glass, and/or an automotive glass comprises aglass article as described herein. An exemplary article incorporatingany of the glass-ceramic articles disclosed herein may be a consumerelectronic device including a housing; electrical components that are atleast partially inside or entirely within the housing and including atleast a controller, a memory, and a display at or adjacent to the frontsurface of the housing; and a cover substrate at or over the frontsurface of the housing such that it is over the display. In someembodiments, at least a portion of at least one of the cover substrateand/or the housing may include any of the glass-ceramic articlesdisclosed herein.

EXAMPLES

In order that various embodiments be more readily understood, referenceis made to the following examples, which are intended to illustratevarious embodiments.

Example 1

Example glass and glass-ceramic compositions (in terms of wt %) andproperties for achieving colored glass-ceramics are set forth inTable 1. Precursor glasses were formed having the compositions 1-9listed in Table 1. Precursor glass A in Table 1 did not include atransition metal oxide colorant. The precursor glasses were thensubjected to a ceramming cycle having a glass homogenization hold at540° C. for 4 hours, a nucleation hold at 600° C. for 4 hours, and acrystallization hold at a temperature of 710° C. for 4 hours.

TABLE 1 Components (wt %) A 1 2 3 4 5 6 7 8 9 SiO₂ 73.6 73.46 72.8873.39 72.88 72.88 72.21 71.88 72.88 72.88 Al₂O₃ 7.6 7.6 7.54 7.59 7.547.54 7.47 7.43 7.54 7.54 Li₂O 11.8 11.16 11.07 11.15 11.07 11.07 10.9710.92 11.07 11.07 Na₂O 1.6 1.59 1.58 1.59 1.58 1.58 1.57 1.56 1.58 1.58B₂O₃ 0.2 0.19 0.19 0.19 0.19 0.19 0.18 0.18 0.19 0.19 P₂O₅ 1.9 2.06 2.052.06 2.05 2.05 2.03 2.02 2.05 2.05 ZrO₂ 3.8 3.75 3.72 3.75 3.72 3.723.69 3.67 3.72 3.72 Au 0 0.09 0 0 0 0 0 0 0 0 Co₃O₄ 0 0 0.93 0 0 0 0 0 00 Cr₂O₃ 0 0 0 0.23 0 0 0 0 0 0 CuO 0 0 0 0 0.93 0 0 0 0 0 Fe₂O₃ 0 0 0 00 0.93 1.84 2.29 0 0 NiO 0 0 0 0 0 0 0 0 0.93 0.93 V₂O₅ 0 0 0 0 0 0 0 00 0.93 Appearance Clear Pink Blue Light Light Light Light Light LightLight grey; of Glass- green blue grayish brownish brownish browntransparent Ceramic green green green Color Coordinates of Glass-CeramicL* 92.9 40.5 26.1 82.5 80.6 89.4 77.4 81.6 54.3 92.9 a* −2.3 32.5 24.0−13.8 −17.4 −3.3 −4.3 −4.3 9.9 −2.3 b* 9.2 −8.0 −51.7 56.3 −18.3 4.313.3 9.0 44.8 9.2 Fracture Toughness of Glass-Ceramic K_(Ic) 1.11 1.111.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 (MPa · m^(1/2))

As shown in Table 1, the inclusion of the transition metal oxidecolorants is effective to change the color of the glass-ceramics madefrom precursor glasses 1-9, without altering the phase assemblage of theglass-ceramic or the fracture toughness (K_(Ic)). In particular, thephase assemblage of each of the glass-ceramics remained petalite andlithium disilicate. Additionally, each of the example glass-ceramics hasa transmittance color coordinate in the CIELAB color space within thefollowing ranges: L*=20 to 90; a*=−20 to 40; and b*=−60 to 60 measuredusing a PerkinElmer Lambda 950 Spectrometer with illuminant F02 underSCI UVC conditions.

The transmittance of glass-ceramics made from precursor glasses 1-9having a thickness of 1 mm was measured for light having a wavelengthfrom 200 nm to 800 nm. As shown in FIGS. 3 and 4, the averagetransmittance of each of the example glass-ceramics was less than 90%.

Example 2

Example glass and glass-ceramic compositions (in terms of wt %) andproperties for achieving colored glass-ceramics are set forth inTable 1. Precursor glasses were formed having the compositions 10-14listed in Table 2. The precursor glasses were then subjected to aceramming cycle having a nucleation hold at 560° C. for 4 hours, and acrystallization hold at a temperature of 760° C. for 1 hour.Transmittance color coordinates for the precursor glass as well as theresultant glass-ceramic are also reported in Table 2.

TABLE 2 Components (wt %) 10 11 12 13 14 SiO₂ 73.4 73.4 72.9 72.9 72.9Al₂O₃ 7.6 7.6 7.5 7.5 7.5 Li₂O 11.2 11.1 11.1 11.1 11.1 Na₂O 1.6 1.6 1.61.6 1.6 B₂O₃ 0.2 0.2 0.2 0.2 0.2 P₂O₅ 2.1 2.1 2.0 2.0 2.0 ZrO₂ 3.8 0 0 00 Au 0.1 0 0 0 0 Cr₂O₃ 0 0.2 0 0 0 CuO 0 0 0.9 0 0 NiO 0 0 0 0.9 0 V₂O₅0 0 0 0 0.9 Color Coordinates of Precursor Glass L* 75.4 90.2 89.4 73.395.8 a* 30.5 −10.2 −9.1 3.4 −0.9 b* 16.5 44.5 −10.1 59.6 2.8 ColorCoordinates of Glass-Ceramic L* 73.3 75.5 81.7 53.8 90.3 a* 29.8 −17.9−4.3 11.7 −1.2 b* 35.9 17.4 9.7 29.1 4.0

The transmittance of glass-ceramics made from precursor glasses 1-9having a thickness of 1 mm was measured for light having a wavelengthfrom 200 nm to 800 nm. As shown in FIGS. 3 and 4, the transmittance ofeach of the example glass-ceramics was less than 90% for points from 400nm to 800 nm.

The transmittance of glass-ceramics (solid lines) and correspondingprecursor glasses (dashed lines) 10-14 having a thickness of 1 mm wasmeasured for light having a wavelength from 200 nm to 1100 nm. As shownin FIGS. 5-9, the transmittance of each of the example glass-ceramicswas less than 90% for points from 400 nm to 1100 nm. Without wishing tobe bound by theory, it is believe that the data depicted in FIGS. 5-9illustrates that the transmittance of the glass-ceramics may be tunedbased on the ceramming conditions employed. Specifically, it is believedthat ceramming the glass for longer periods of time (thereby creating agreater percentage of the ceramic phase(s) in the glass ceramic) maydecrease the transmittance of the glass-ceramics. As such, controllingthe ceramming conditions may be used to tune the transmittance of theglass-ceramics.

Accordingly, various embodiments described herein provide coloredglass-ceramics having high strength and fracture toughness. Inparticular, various embodiments include one or more colorants in theform of transition metal oxides which impart color to the glass-ceramicwithout altering the phase assemblage of the glass-ceramic or adverselyimpacting the strength and/or fracture toughness of the glass-ceramic.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments describedherein without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various embodiments described hereinprovided such modification and variations come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A glass-ceramic article comprising: a petalitecrystalline phase; a lithium silicate crystalline phase; and one or morecolorants selected from the group consisting of TiO₂, Fe₂O₃, NiO, Co₃O₄,MnO₂, Cr₂O₃, Au, and V₂O₅, wherein a weight percentage of each of thepetalite crystalline phase and the lithium silicate crystalline phase inthe glass-ceramic article are greater than each of the weightpercentages of other crystalline phases present in the glass-ceramicarticle; and wherein the glass-ceramic article has a transmittance colorcoordinate in CIELAB color space of: L*=from 20 to 90; a*=from −20 to40; and b*=from −60 to 60 for a CIE illuminant F02 under SCI UVCconditions.
 2. The glass-ceramic article according to claim 1, whereinthe glass-ceramic article has a composition comprising, in wt %: SiO₂ inan amount of from 55 to 80; Al₂O₃ in an amount of from 2 to 20; Li₂O inan amount of from 5 to 20; P₂O₅ in an amount of from 0.5 to 6; and ZrO₂in an amount of from 0.2 to
 15. 3. The glass-ceramic article accordingto claim 2, wherein the composition further comprises, in wt %, from0.01 to 5 of the one or more colorants.
 4. The glass-ceramic articleaccording to claim 3, wherein at least 80 wt % of the one or morecolorants in the composition is present in a residual glass phase of theglass-ceramic article.
 5. The glass-ceramic article according to claim3, wherein at least 95 wt % of the one or more colorants in thecomposition is present in a residual glass phase of the glass-ceramicarticle.
 6. The glass-ceramic article according to claim 2, wherein thecomposition further comprises, in wt %: Au in an amount of from 0.1 to1.5; or Cr₂O₃ in an amount of from 0.05 to 1.0; or NiO in an amount offrom 0.1 to 2.0; or V₂O₅ in an amount of from 0.1 to 2.0; or Co₃O₄ in anamount of from 0.01 to 2.0.
 7. The glass-ceramic article according toclaim 6, wherein the glass-ceramic article has a transmittance colorcoordinate in the CIELAB color space of: L*=from 50 to 90; a*=from −20to 30; and b*=from 0 to 40 for a CIE illuminant F02 under SCI UVCconditions.
 8. The glass-ceramic article according to claim 1, whereinthe one or more colorants selected from the group consisting of NiO,Co3O4, MnO2, Cr2O3, Au, and V2O5.
 9. A glass-ceramic article comprising:a petalite crystalline phase; a lithium silicate crystalline phase; anda residual glass phase comprising a colorant, wherein the colorantcomprises one or more colorants selected from the group consisting ofTiO₂, Fe₂O₃, NiO, Co₃O₄, MnO₂, Cr₂O₃, Au, and V₂O₅; wherein: theglass-ceramic article has a fracture toughness of 1 MPa·m^(1/2) orgreater; and the glass-ceramic article has a transmittance colorcoordinate in CIELAB color space of: L*=from 20 to 90; a*=from −20 to40; and b*=from −60 to 60 for a CIE illuminant F02 under SCI UVCconditions.
 10. The glass-ceramic article according to claim 9, whereinthe glass-ceramic article has a composition comprising, in wt %: SiO₂ inan amount of from 55 to 80; Al₂O₃ in an amount of from 2 to 20; Li₂O inan amount of from 5 to 20; P₂O₅ in an amount of from 0.5 to 6; and ZrO₂in an amount of from 0.2 to
 15. 11. The glass-ceramic article accordingto claim 10, wherein the composition further comprises, in wt %, from0.01 to 5 of the one or more colorants.
 12. The glass-ceramic articleaccording to claim 9, wherein at least 80 wt % of the colorant ispresent in the residual glass phase of the glass-ceramic article. 13.The glass-ceramic article according to claim 9, wherein at least 95 wt %of the colorant is present in the residual glass phase of theglass-ceramic article.
 14. The glass-ceramic article according to claim10, wherein the composition further comprises, in wt %: Au in an amountof from 0.01 to 1.5; or Cr₂O₃ in an amount of from 0.05 to 1.0; or NiOin an amount of from 0.1 to 2.0; or V₂O₅ in an amount of from 0.1 to2.0; or Co₃O₄ in an amount of from 0.01 to 2.0.
 15. The glass-ceramicarticle according to claim 14, wherein the glass-ceramic article has atransmittance color coordinate in the CIELAB color space of: L*=from 50to 90; a*=from −20 to 30; and b*=from 0 to 40 for a CIE illuminant F02under SCI UVC conditions.
 16. The glass-ceramic article according toclaim 9, wherein each of the petalite crystalline phase and the lithiumsilicate crystalline phase in the glass-ceramic article have greaterweight percentages than other crystalline phases present in theglass-ceramic article.
 17. The glass-ceramic article according to claim9, wherein the one or more colorants selected from the group consistingof NiO, Co₃O₄, MnO₂, Cr₂O₃, Au, and V₂O₅.
 18. A glass-ceramic articlecomprising: a petalite crystalline phase; and a lithium silicatecrystalline phase, wherein: each of the petalite crystalline phase andthe lithium silicate crystalline phase in the glass-ceramic article havegreater weight percentages than other crystalline phases present in theglass-ceramic article; the glass-ceramic article comprises one or morecolorants selected from the group consisting of TiO₂, Fe₂O₃, NiO, Co₃O₄,MnO₂, Cr₂O₃, Au, and V₂O₅; and the glass-ceramic article has atransmittance color coordinate in CIELAB color space of: L*=from 50 to90; a*=from −20 to 30; and b*=from 0 to 40 for a CIE illuminant F02under SCI UVC conditions.
 19. The glass-ceramic article according toclaim 18 further comprising, in wt %: SiO₂ in an amount of from 55 to80; Al₂O₃ in an amount of from 2 to 20; Li₂O in an amount of from 5 to20; P₂O₅ in an amount of from 0.5 to 6; and ZrO₂ in an amount of from0.2 to
 15. 20. The glass-ceramic article according to claim 18, whereinthe glass-ceramic article has a fracture toughness of 1 MPa·m^(1/2) orgreater.
 21. The glass-ceramic article according to claim 18, whereinthe glass-ceramic article has a Vickers hardness of 600 kgf/mm² orgreater.
 22. The glass-ceramic article according to claim 18, whereinthe glass-ceramic article has a ring-on-ring strength of at least 300MPa.
 23. The glass-ceramic article according to claim 18, wherein theone or more colorants selected from the group consisting of NiO, Co₃O₄,MnO₂, Cr₂O₃, Au, and V₂O₅.
 24. The glass-ceramic article according toclaim 18, wherein the glass-ceramic article comprises 0.01 wt. % to 5wt. % of the one or more colorants.